Elastic-fluid turbine.



No. 887,361. PATENTED MAY 12, 1908. E. P. WAGNER.

BLASTIC FLUID TURBINE.

APPLICATION HLED H1B. 11, 1907.

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/r7 Venlor': E pau/ Wa ner',

Mam b l y", v .2f/bg ERNST PAUL WAGNER,

OF OHARLOTTENBURG, GERMANY, ASSIGNOR TO GENERAL ELlllOTRIC COMPANY, A CORPORATION OF NEW YORK.

ELASTIC-FLUID TURBINE.

Specification of Letters Patent.

Patented May 12, 1908.

' Application filed February 11, 1907. Serial No. 886,705.

To all whom it may concern:

Be it known that l, ERNST PAUL WAGNER,

a citizen of the German Empire, residing at Charlottenburg, Germany, have invented certain new and useful Improvements in Elastic-Fluid Turbines, of which the following is a specification.

My invention has for its object to provide a turbine of improved construction which is capable of' operating with high efliciency both at maximum and moderate loads, and this without subjecting the wheel casing or casings to excessive strains.

In the accompanying drawing, which illustrates one of the embodiments of my invention, Figure 1 is a longitudiiialsection of a turbine; and Fig. 2 is a curve showing the relation of the pressures inl the different stages.

1 represents a casing having a suitable inlet 2 and an exhaust conduit 3. The buckets Ltare mounted on suitable wheels and the latter are carried by a shaft 5 mounted in as steam for example,

bearings 6. On the shaft are thrust collars 7, the casing therefor being removed, to take the end thrust of the shaft, as for example Where the machine is intended to drive a propeller for marine purposes. The wheels are rovided. with two rows of buckets in the 'gh-pressure stages and single rows in the lowressure stages. Between the stages and orming walls thereof are diaphragmsv or partitions 8 which support or contain the nozzles 9. The initial nozzle or nozzles 10 is or are constructed and arranged to have a greater ratio of ex ansion than the nozzles 9 etween stages, t ereby creating a greater pressure drop and avoiding the strains on the casin incident to hi h pressure. This is especia ly important wiere the initial pressure is high and the diameter of the wheel casing large. The admission of motive iluid, such to the initial nozzle or nozzles is controlled by one or more valves 11. As shown the valve is operated by hand but it may be operated by a suitable motor in response to load changes, as is well under stood. v

At some intermediate point in the turbine a stage of special construction is provided which for the purpose of distinguishing it from the others may be called the auxiliary overload stage. This stage" comprises a Awheel 12 that is mounted on tliemain shaft and is provided with one, two or more rows of buckets. ln the present instance two rows are shown with intermediate buckets 13 4between and acting to extract energy from thef motive fluid by successive operations. High-pressure fluid is admitted to the stage by one or more nozzles 14 having a ffreater ratio of expansion than the stage nozz es 9 so as to create a greater pressure drop and thereby reduce the pressure in the wheel chamber and consequently the strains on the casing. 'lhis stage is normally in operation only under conditions of overload, as will appear later.

Steam or other elastic fluid is admitted to the nozzle or nozzles by the conduit 14 containing a throttle valve 15 that in the present illustration of the invention is actuated by hand, but which may be operated automaticall in response to a governor in a manner we l understood.

Located on the outside of the casing or at sonic other convenient point is a conduit 16 which normally shunts the motive fluid past the overload stage and thereby renders it inactive. In this conduit isy an automatic valve 17 which openswhen fluid under pressure is admitted to the machine by the valve 11 and closes automatically when the valve 1.5 is opened and the valve 11 closed. A suitable stop 18, which may be adjustable, is arranged to limit the opening of the valve. The conduit 16 is shown as being bolted to the outside of the casing, since this is a convenient arrangement, but it may be formed in the casing itself if desired. Only one of these conduits is shown in the illustration, but itis to be understood that two, three or more may be rovided if desired to handle the volume of uid.

Under conditions of from' moderate up to full load, for example. the motive fluid enters the turbine through the valve 11 and nozzles 10 where it expands to a relatively low pressure and the energy is converted into velocity and the wheel and intermediate buckets convert the velocity into useful work. The fluid is then reiiozzled, and the o eration repeater It then`passes through t e conduit 16 into the stagecoinpartment containing the overload wheel. lt does no work in this compartment but passes through the adjacent nozzles into' the next sta lower pressure where the conversion o energy into useful work is continued. Instead -bf passing through three stages before entering the compartment of the overload Wheel, it may pass through only one or two. Where the load conditions are satisfied by such an arrangement, a conduit 1Q is provided which shunts4 the motive fluid past two rows of Wheel buckets and discharges it either into the compartment of the overload Wheel or to a compartment beyond if desired. This conduit is provided with a regulating valve 2() of suitable construction. Assuming now a load condition greater than the normal and approaching the maximum overload, thevalvc 11 is closed and the valve 17 drops to its seat and the valve 15 is opened. The entering iluid is expanded by the nozzle 14 to a point Where the pressure within the compartment will not be injurious to the casing. The velocity of the 'luid leaving the nozzle or nozzles is converted into useful work by the wheel 12 by successive operations. After the fluid leaves the wheel it is renozzled and the operation repeated until the available energy is extractedafter which it leaves the turbine by the conduit 3.

The turbine shown is so designed that it operates most efficiently under conditions of maximum steam consumption. In Fig. 2 are shown curves representing the pressures in the different stages under different load conditions. c represents the pressure of the source of supply and b the pressure in the auxiliary or overload stage. From this point the pressure drops from stage to stage y small amounts until it reaches c which corres onds with the exhaust.

If t e machine, including the auxiliary or overload and the subsequent stages, was regulated by throttlin g, the pressure curve at light loads would be represented by d, e, c, the thermo-dynamic efficiency falling rapidly as the supply of motive fluid Was decreased. In order to improve the economy of a turbine operating under these conditions, it has been proposed to interpolate a turbine between the main turbine and the source of supply, in which case the pressuredrop a d is utilized therein. The pressure conditions in the system are then as represented by f d e c, in which case the pressures in the stages of the interpolated machine are represented kby the lengths of the. lines r/ /L i and are greatly in excess o'f pressure l; which is considered a safe Working pressure i'or a machine 'of given diameter. It is therefore apparent that with such arrangement the interpolated machine must either have a much smaller diameter, or else it can be used only with very much sm aller loads where the pressure is materially less. With all except the overload stagein service, the pressure curve will be represented byfj /c c. It will be noted that the pressure at j, initial stage, is the same as that at b, auxiliary stage, Whereas with the previous arrangements it would have to be much higher, as represented by the points of intersection of the lines g 7i i and the dotted line This arrangement also has the advantage oi better utilizing the drop vin pressurebetWeen d and e. It will thus be seen that my invention overcomes the objections above noted and the Wheels and casing can have diameters best suited for the Work the early stages can be utilized even with comparatively heavy loads Without 'causing undue strains, and the machine as a Whole will have a high elhciency.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof; but I desire to have it understood that the apparatus shown is only illustrative, and that the invention can be carried out by other means.

That I claim as new and desire to secure by Letters Patent of the United States, is,

1. A- turbine comprising a plurality ot stages, one of which is inactive for certain load conditions, and means for cutting one or more stages out of operation and for cutting said inactive stage into service for other load conditions.

2. A turbine comprising a plurality ol stages arranged to handle certa-in predetermined loads, an auxiliary stage which is inactive for said loads, and means for cutting one or more of the iirst-mentioned stages out of and the auxiliary stage into service for other loads.

3. A turbine comprising a plurality of stages including? an initial and an overload stage, iluid discharging devices for the stages, those of the initial and overload stages having a greater ratio of expansion than those of the -remaining stages, and means for controlling the admission of fluid to the initial and overload stages. p

4i. A turbine comprising a plurality ot stages, including an initial and one which is operative only under heavy load conditions, fluid-discharging devices for the stages, those of the initial and heavy load stages having a greater ratio ot' expansion than those of ty il@ other stages to prevent excessive casing strains, and means for cutting one or more stages out of operation and the heavy load stage into operation.

5. A turbine comprising a plurality oi stages, one of the intermediate of which is operative only under conditions of overload, huid-discharging devices for the several stages, those of the initial and overload stages having a greater ratio of expansion than those of the other stages, and means for cutting the initial stage and overload stages into and out of communication With a source of supply.

6.' A .turbine comprising a plurality of' stages some of which are only 1n operation iis lfor certain loads, While the remainder are always in operation, an auxiliary stage which is in operation only` at certain loads, a conduit for shunting the auxiliary stage at certain loads, andmeans for cutting -out the initial stage, closing the shunt conduit, and admitting fluid to the auxiliary stage' for other load conditions.

7. A turbine comprising a plurality of stages arranged in series to receive motive fluid for certain load conditions, an auxiliary stage that is operative under different load conditions and discharges into the low-pressure stages, a conduit for shunting the auxiliary stage While the remaining stages are in operation, a valve in the conduit for interrupting the assagc of fluid, means for cutan means for admitting i tin the hig -pressure sta es out of service,

(rh-pressure motive fluid to the auxiliary and the succeeding stages.

8. An elastic-fluid turbine comprising a Iilurality of low-pressure stages, two or more 1gb-pressure stages, independent conduits admitting motive fluid to the turbine in such manner as to cause it to act in different highpressure stages, valve means for controlllng the assage of fluid throvugh the conduits, an aux iary stage which is normally inactive, and means for closing the high-pressure stages a ainst the admission of fluid when the auxi iary staffe is inserted.

9. An elastic-iluid turbine comprising a plurality of stages each containing buckets and devices disdharging motive fluid against the buckets, independent conduits for admitting motive fluid to the initial stage and also to subsequent and lower-pressure stages, and,

a valve which automatically closes When fluid is admitted to one of the lower-pressure stages to revent it from filling the preceding portion o the turbine.

In witness whereof, l have hereunto set my hand this 9th day of January, 1907.

E. PAUL WAGNER. Witnesses: WALTHER' FRITZ,

ALFRED BETTMANN. 

